The present invention relates generally to fluid pumps and pertains particularly to an improved rotary disc pump.
Rotary disc pumps have been generally known for a considerable length of time but little used until recent years. The rotary disc pump utilizes an impeller having a plurality of generally planar discs having an open center mounted on and spaced axially along a rotary shaft. The rotating discs utilize surface drag or boundary layer friction of the planar surfaces of the discs to propel a fluid through the pump. In the past such disc pumps have been unable to compete effectively with positive displacement pumps and bladed impeller pumps for the pumping of fluids for most applications.
The applicant has in recent years, developed improvements in disc pumps that made them commercially practical for the pumping wide variety of liquids and materials in liquids including slurries and the like. As a result of these improvements, rotary disc pumps have come into widespread use in many applications where traditional positive displacement pumps and bladed impeller pumps are not practical. While disc pumps will not replace positive displacement pumps and bladed impeller pumps in most applications, they have begun to replace them in many applications where such positive displacement and bladed impeller pumps are unsuitable.
The suitable applications for disc pumps include highly viscous materials and fluids containing solids, both hard and delicate. These applications occur particularly in the food and pharmaceutical industries, where there are many delicate and fragile shear and impact sensitive materials that can be easily damaged with positive displacement pumps and bladed impeller pumps. For this reason these materials cannot be satisfactorily pumped or transported with these pumps. The moving blade of impeller pumps can impact and bruise or otherwise cause damage to delicate and fragile materials.
The disc pump has begun to be widely used in the food processing and pharmaceutical industries for many applications including the pumping of liquids. In the pumping of many liquids, particularly in these industries, it is important that the inclusion of gas or air in the liquid be minimized. The present invention has been discovered to greatly reduce and in many instances eliminate generation or inclusion of air bubbles and the like in such liquids.
Accordingly there is a need for an improved pump for the pumping of delicate shear and impact sensitive materials that reduces entrapped air and gasses.
It is therefore desirable to have an improved pump for handling of delicate and other difficult to pump materials.